Chap. XVI. INHERITANCE, LIMITED BY AGE. 185 



aria. In almost the whole large group of thruslies 

 the young have their breasts spotted — a character 

 which is retained by many species throughout life, 

 but is quite lost by others, as by the Turdus migra- 

 tortus. So again with many thrushes, the feathers on 

 the back are mottled before they are moulted for the 

 first time, and this character is retained for life by 

 certain eastern species. The young of many species of 

 shrikes (Lanius), of some woodpeckers, and of an Indian 

 pigeon (CJialcopha^s Indicus), are transversely striped 

 on the under surface ; and certain allied species or 

 genera when adult are similarly marked. In some 

 closely-allied and resplendent Indian cuckoos (Chryso- 

 coccyx), the species when mature differ considerably 

 from each other in colour, but the young cannot be dis- 

 tinguished. The young of an Indian goose {Sarkidiornis 

 melanonotus) closely resemble in plumage an allied 

 genus, Dendrocygna, when mature.^ Similar facts will 

 hereafter be given in regard to certain herons. Young 

 black grouse (Tetrao tetrix) resemble the young as well 

 as the old of certain other species, for instance the red 

 grouse or T. scoticus. Finally, as Mr. Blyth, who has 

 attended closely to this subject, has well remarked, the 

 natural affinities of many species are best exhibited in 

 their immature plumage ; and as the true affinities of 

 all organic beings depend on their descent from a 

 common progenitor, this remark strongly confirms the 

 belief that the immature plumage approximately shews 

 us the former or ancestral conditioli of the species. 



* In regard to thrushes, shrikes, and woodpeckers, see Mr, Blytli, in 

 Charlesworth's ' Mag. of Nat. Hist.' vol. i. 1837, p. 304 ; also footnote 

 to his translation of Cuner's ' Regno Animal,' p. 159. I give the ease 

 of Loxia from Mr. Blyth's information. On thrushes, see also Audubon, 

 'Ornith. Biography,' vol. ii. p. 195. On Chrysocoecyx and Chal- 

 cophaps, Blyth, as quoted in Jerdon's ' Birds of India,' vol. iii. p. 485. 

 On Sarkidiornis, Blyth, in 'Ibis,' 18G7, p. 175. 



